The F135 is an afterburning turbofan engine developed for the F-35 Lightning II, a single-engine Joint Strike Fighter. The F135 family are available in different variants according to the F-35 model —a conventional, forward-thrust variant (for the F-35A and F-35C) and a multi-cycle, short take-off vertical landing variant that includes a forward lift fan for the F-35B.

Pratt & Whitney’s New F135 Fan, Compressor Pass Critical Tests

Pratt & Whitney reports that the newest model of its F135 engine, the turbofan jet engine that powers the Lockheed Martin-built F-35 Lightning II, successfully demonstrated "full-life capability" for its cold section – meaning the fan and compressor components. The results were concluded following accelerated mission testing (AMT) at the Arnold Engineering Development Complex, at the Arnold Air Force Base in Tullahoma, Tenn.

The engine being tested is the fifth generation of the F-135. Pratt & Whitney is working with the U.S. Navy and U.S. Air Force to implement increases in thrust and improved fuel-burn rates. According to reports, the plans include better cooling technology for turbine blades, which would increase engine longevity and cut maintenance costs.

In the specific testing reported by P&W, the engine achieved 9,400 total accumulated cycles (TAC), equivalent to approximately 14 years of operation, or approximately 2,000 F-35 missions. The testing was completed while running the engine at extreme conditions to simulate operational engines.

Pratt & Whitney builds the engines at its plants in Middletown, Conn., and West Palm Beach, Fla. Each engine is the sole power source for the F-35, the Stealth-enabled Joint Strike Fighter aircraft designed for ground attack and combat. The U.S. Dept. of Defense recently approved funding for the “low-rate initial production” sequence of Lot 11 for the F-35 program.

"Demonstrating the full life capability of the F135 engine's cold section represents a key milestone for the program," stated P&W’s John Wiedemer, v.p. - F135 Program. He noted the results follow successful full-life testing of the F135's hot section in 2015.

“This shows we have a robust propulsion system capable of providing full-mission capability to the warfighter," he added.

AMT tests and validates reliability and maintainability performance for the engine over the span of its life. It also helps identify potential problems before they would be encountered in operational service.

The test was focused on the Conventional Takeoff and Landing (CTOL) engine variant that powers the F-35A and F-35C models. Testing took place between August 2014 and October 2017, and consisted of two hot section intervals, which is equivalent to the cold section life.